Based on day 29 bone marrow results, patients may start consolidation therapy, undergo retesting in a week, or receive 2 additional weeks of therapy. Additional therapy comprises oral prednisone thrice daily for 14 days; vincristine sulfate IV and daunorubicin hydrochloride IV over 15-20 minutes on days 29 and 36; and IM pegaspargase on day 29, 30, or 31. After successful remission induction, patients are assigned to COG-P9904, COG-P9905, or COG-P9906 based on the classification study.